1. Technical Field
Example embodiments of the present invention relate in general to a method for generating a random access signal, and more specifically, to a method for generating a random access signal of a machine type communication device using a narrow bandwidth.
2. Related Art
Machine type communication (MTC) or machine-to-machine communication means data communication related to one or more entities that does not require human intervention.
A service optimized for MTC is different from a service optimized for human-to-human communication. MTC is different from the existing mobile network communication relating to characteristics such as a) various market scenarios, b) data communications, c) lower cost and effort, d) many potential communicating terminals, e) large range, and f) small traffic for each terminal.
Examples of the type of MTC service include smart metering, tracking & tracing, remote maintenance & control, and e-health.
Recently, 3GPP (3rd Generation Partnership Project) is standardizing machine type communication (MTC) for human-to-machine communication and machine-to-machine intelligent communication. Many MTC devices are arranged and operated for various MTC applications that have smart metering and remote control as main functions.
In a 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) system, since an MTC device or a general user is treated as one user equipment (UE), it should be separately registered in an LTE network. The arrangement of many MTC devices causes scheduling contention for channel allocation, depletion of wireless resources, overload by signal generation, and adversely affects the existing general terminals. 3GPP is performing standardization, concentrating on minimizing the adverse effects caused by the arrangement of MTC devices. In addition, effort is being made to provide low-cost MTC devices to extend MTC service through LTE.
In this regard, all LTE-based UEs are standardized to support a transmission/reception bandwidth of up to 20, MHz. Accordingly, a general LTE UE, which is a legacy terminal from the viewpoint of an MTC device, can access a base station (eNodeB) having a 1.4, MHz, 3, MHz, 5, MHz, 10, MHz, 15, MHz or 20, MHz bandwidth. In general, an MTC device or terminal transmits a very small amount of information. Therefore, supporting a bandwidth up to 20, MHz for an MTC device as with a general UE may be a considerable waste of cost from the viewpoint of an MTC device aiming at low cost.
In order to solve this problem, discussions are being held to have MTC devices operate with a narrow bandwidth. That is, while a base station uses a wide bandwidth, an MTC device uses a narrow bandwidth of up to 1.4, MHz or 5, MHz. To this end, there is a need to provide a separate wireless transmission standard for supporting communication between a base station and an MTC device having a narrow bandwidth.